Ultrafast isomerization dynamics of retinal in bacteriorhodopsin as revealed by femtosecond absorption spectroscopy  

作　　者：WU YiShi ZHONG Sheng AI XiCheng HU KunSheng ZHANG JianPing 

机构地区：[1]Slate Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China [2]Institute of Biophysics, the Chinese Academy of Sciences, Beijing 100101, China [3]Department of Chemistry, Renmin University of China, Beijing 100872, China

出　　处：《Chinese Science Bulletin》2008年第13期1972-1977,共6页

基　　金：the National Natural Science Foundation of China (Grant Nos.20673144 and 20433010)

摘　　要：A femtosecond (fs) broad-band absorption apparatus was used to measure the early photoisomeriza-tion process of bacteriorhodopsin’s (BR) photocycle to reveal the character of the important interme-diate of J625 and to obtain a deeper understanding of the role of photoisomerization in BR photocycle. Two time constants of 0.5 ps (95%) and 2.0 ps (5%) were brought out by global fitting on thirty curves in the near-infrared region. We suggest that the first time constant results from the decay of I460 interme-diate,and the longer component might be associated with BR isomer. The global analysis over 450,540,630,710 and 870 nm traces identified two time constants,～0.5 and～3 ps. The slower component can be extracted from the processes of both J625→BR568 (540 nm) and J625→K590 (630 nm),suggesting J-in-termediate takes a partial cis configuration. The obvious negative feature in early delay time of 700―780 nm regions was attributed to the radiative transition (stimulated emission) from the Franck-Condon active configuration along the isomerization potential surface of all-trans-retinal.A femtosecond （fs） broad-band absorption apparatus was used to measure the early photoisomerlzation process of bacteriorhodopain＇s （BR） photocycle to reveal the character of the important Intermediate of J625 and to obtain a deeper understanding of the role of photoisomerizaUon in BR photocycle. Two time constants of 0.5 pa （95%） and 2.0 pa （5%） were brought out by global fitting on thirty curves In the nser-lnfrared reglon. We suggest that the first time constant results from the decay of I480 intermediate, and the longer component might be associated with BR isomer. The global analysis over 450, 540, 630, 710 and 870 nm traces identified two time constants, -0.5 and -3 pa. The slower component can be extracted from the processes of both J625→BR568 （540 nm） and J625→K590 （630 nm）, suggesting J-intermediate takes a partial cis configuration. The obvious negative feature in early delay time of 700- 760 nm reglona was attributed to the radiative transition （stimulated emission） from the Franck-Condon actlve conflguratlon along the isomerization potential surface of all-trans-retinal.

关 键 词：光致异构化 受激发射 球状配件 噬菌调理素 

分 类 号：O43[机械工程—光学工程]